Poster presented at the ASLO conference in Granada, Spain in 2015

DEVELOPMENT OF AN ARCTIC LAKE OBSERVATORY AT TESHEKPUK LAKE: Teshekpuk Lake is the largest Arctic lake in Alaska. It has a surface area of 850 km2, a watershed area of 2,750 km2, and a maximum depth of 7 m. It is located in the continuous permafrost zone, 15 km from the Arctic Ocean, and is roughly 2 m asl. The lake provides habitat for 14 fish species and likely influences the regional climate creating important habitat for caribou, geese, and other wildlife. Teshekpuk Lake is the ideal location for establishing an Arctic lake observatory - given sea-level rise projections, rapid erosion along the Beaufort Sea coast and Teshekpuk Lake shore, permafrost thaw and land subsidence, climate change impacts to aquatic and terrestrial ecosystems, as well as the potential for oil and gas development in the watershed. Teshekpuk Lake also provides an ideal calibration and validation site for remote sensing missions due to its size and location. Here we introduce the Teshekpuk Lake Observatory (TLO) and its research infrastructure, and present findings based on data collected from sensor networks, remotely sensed imagery, paleoecological analyses, and limnological surveys.

Presentation Given at the Alaska Water Resources Association annual meeting in 2011

The Hydrology and Ice Cover of Teshekpuk Lake in a Changing Arctic Climate: At 850 km2, Teshekpuk Lake is the third largest freshwater inland lake and the largest Arctic lake in Alaska, and possibly the largest thermokarst lake in the world. Although set on the Arctic Coastal Plain (ACP) only a meter above sea level with maximum depth reaching < 7 m, Teshekpuk Lake has very fresh water, partly owing to runoff from Keolok Creek that drains a ~1200 km2 area of sand sea to the south. Teshekpuk Lake provides habitat for at least 14 species of fish, hosts an abundant population of a marine invertebrate Saduria entomon, and likely has important influences on the regional land and climate that make this area important habitat for caribou, geese, and other wildlife. Because of its immense size and position near the Beaufort Sea coastline, ice cover typically persists well into July and occasionally mid-August or later making this the last lake in the state to completely lose its ice cover. Thus, open-water duration at Teshekpuk Lake persists at most for 3 months, more commonly for 2 months, and potentially may maintain perennial ice-cover during some years. Thus, the ice-cover regime likely plays a key role in its long-term hydrological and limnological behavior. Thus to better understand the relationship between ice-cover and hydrology on Teshekpuk Lake, we estimated ice-cover regimes from 1947 to present using air temperature records from Barrow calibrated to local weather and lake stations and verified with remotely sensed imagery from 1973 to 2010, and field observations from 2007 to present. For this 62 year period, average ice-out timing was 29-July (±14 d SD) with the earliest date of 7-July in 1998 and a trend towards earlier ice-out of 0.4 d/yr (r2=0.27) was found. Average ice-on timing was 22-September (±11 d SD) with the latest date of 10-October in 1954 and no trend in ice-on timing. Ice-free duration averaged 55 days (±21 d SD) with the longest duration estimated to occur in 1998, 91 days. These results also suggest that Teshekpuk Lake had at least partial, perennial ice cover during the summers of 1956 and 1969. Using downscaled composite output from five global climate models for the A1B emissions scenario, we predicted future ice-cover timing and duration for Teshekpuk Lake based on empirical relationships to mean monthly air temperature, which as expected show a continued trend toward longer open-water duration. Both the timing of ice-cover and its duration may have important affects on the water balance of Arctic lakes because of how it regulates water temperature and evaporative losses during short summers. In the case of Teshekpuk Lake, its large surface area relative to volume and watershed area may make it particularly vulnerable to longer periods of evaporation in years with below normal rainfall. Making improved predictions about this important water resource and ecosystem of the Alaskan ACP will benefit from the long-term monitoring program we have established for Teshekpuk Lake, its watershed, and climate system. Citation:Arp, C. , Jones, B.(2011). The Hydrology and Ice-cover of Teshekpuk Lake in a Changing Arctic Climate. Retrieved from Alaska Section of the American Water Resources Association 2011 Conference Proceedings Web site:http://www.awra.org/state/alaska/proceedings/2011abstracts/